#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <vector>

using namespace std;

int missingNumber(const vector<int>& nums) {
    int ret = 0;
    int n = nums.size();
    for (int i = 0; i < n; ++i)
        ret ^= nums[i];

    for (int i = 0; i <= n; ++i)
    {
        ret ^= i;
    }

    return ret;
}

int main()
{
    missingNumber({ 0,2,3 });
	return 0;
}